Minerals, Rocks, and Soil Minerals, A Science A–Z Earth Series Word Count: 1,748 Rocks, and Soil Written by Rachel Kamb Visit www.sciencea-z.com www.sciencea-z.com KEY ELEMENTS USED IN THIS BOOK Minerals, Rocks, The Big Idea: Earth is made up of various living and nonliving materials. Elements form minerals, and minerals form rocks. Each mineral and rock can be classified in many ways. Igneous, sedimentary, and metamorphic rocks form differently and can transform through the rock cycle. Through and Soil weathering and erosion, rocks change, break, and move. Minerals mix with organic material, forming the soil on which plants and animals rely. People use nonliving materials as resources by mining, drilling, and refining them. While seemingly abundant, Earth’s resources are limited and must be preserved for future generations. Key words: bedrock, crystal, deposit, drill, element, energy resources, erosion, fossil, humus, igneous rock, inorganic, lava, magma, matter, metal, metamorphic rock, mine, mineral, ore, organic, process, raw material, refine, resources, rock, rock cycle, sedimentary rock, soil, subsoil, topsoil, weathering Key comprehension skill: Main idea and details Other suitable comprehension skills: Compare and contrast; classify information; cause and effect; identify facts; elements of a genre; interpret graphs, charts, and diagrams; using a glossary and boldfaced terms; using a table of contents and headings Key reading strategy: Connect to prior knowledge Other suitable reading strategies: Ask and answer questions; summarize; visualize; retell Photo Credits: Front cover (tl): © iStockphoto.com/Gilles Glod; front cover (tc), pages 7, 8 (3), 20 (tr, cl): Casey Jones/© Learning A–Z; front cover (tr): © iStockphoto.com/malerapaso; front cover (cl): © iStockphoto.com/ Martin Novak; front cover (c): © iStockphoto.com/Jakub Krechowicz; front cover (cr), page 8 (1): © iStockphoto.com/ Fabrizio Troiani; front cover (bl): © Igor Baz/123RF; front cover (bc): © iStockphoto.com/Jacob VanHouten; front cover (br): © iStockphoto.com/Jill Fromer; front cover (background): © iStockphoto.com/Selahattin Bayram; back cover, page 8 (4): © iStockphoto.com/Jodi Jacobson; title page: © iStockphoto.com/Agnes Csondor; page 3: © iStockphoto.com/hsvrs; page 4: © iStockphoto.com/Jason Floyd; page 5 (top): © Jelena Zaric/123RF; page 6 (top): © iStockphoto.com/Don Wilkie; page 6 (b): © iStockphoto.com/Rainer Walter Schmied; pages 8 (2), 20 (tl): Doug Tepper/© Learning A–Z; page 8 (5): © iStockphoto.com/Nikola Miljkovic; page 8 (6): © iStockphoto.com/Max Delson Martins Santos; pages 8 (7), 10 (t): © iStockphoto.com/stockcam; page 8 (8): © iStockphoto.com/Anandha Krishnan; page 9: © DK Images; 10 (t): © O. 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It has water for drinking and air for breathing. It is home to plants and animals, which you need for so many reasons. But Table of Contents don’t forget one more important thing Earth Introduction ........................................................ 4 provides: land! Elements and Minerals ...................................... 5 The land is where you walk and where you Rocks .................................................................... 7 play. Your home is built on land. But what is land made of? Why is it important? In Rock Groups ....................................................... 9 this book, you will learn about nonliving Igneous Rocks ................................................... 9 Earth materials that make up the land. Sedimentary Rocks .......................................... 11 Metamorphic Rocks......................................... 13 Nonliving Earth The Rock Cycle ................................................. 14 materials differ a lot from one Weathering and Erosion .................................. 15 place to another. What Is Soil? ..................................................... 17 They come in Kinds of Soil ...................................................... 18 many colors, Layers of Soil ..................................................... 19 shapes, and sizes, and can change Using Earth’s Resources .................................. 21 quite a bit. They Conclusion ........................................................ 22 also help you in Glossary ............................................................. 23 ways you may This home and the land it sits on are not realize. Index .................................................................. 24 made of nonliving Earth materials. 3 4 Elements and Minerals elements → minerals → rocks To start thinking about what Earth is made A mineral is a natural of, let’s start small . really small. Elements substance made of elements. are what make up all matter, both living and Some minerals, including Silver is a mineral nonliving. Everything on Earth many kinds of metal, consist made of one element. is made from just over one of just one kind of element. For example, silver hundred different elements. is only made of silver, and iron is only made Carbon, helium, and zinc of iron. Many other minerals consist of two are a few of these elements. or more elements. For example, quartz is made of the elements silicon and oxygen. elements → minerals → rocks Earth has nearly 4,000 different minerals. Each one has its own mixture of elements. PERIODIC TABLE OF THE ELEMENTS All minerals are solid, and they form in a pattern of crystals. Minerals have crystals Sr because their atoms are arranged in tidy Cs Cesium patterns. Different Ds Rg Cn Fl Lv Darmstadtium Roentgenium Copernicium Flerovium Livermorium patterns make different crystal This table lists all the known elements on Earth. Each box shapes. Minerals has a symbol for the element and more information about it. are also inorganic. This means they are not living, Elements are not the smallest parts and they were of matter. The tiniest bits of each never alive. Quartz is made of two elements. element are called atoms. Can you see the pattern made by the minerals? 5 6 Rocks You can describe a rock in many ways. You can also compare one rock with another. Read What happens when minerals combine? the chart to learn some ways to describe and A rock is a hard, solid material found in compare rocks. nature. Most rocks are made of different minerals, just as a salad is made of different HOW TO DESCRIBE AND COMPARE ROCKS vegetables. If you pick up a rock, you might Mineral Rocks have a special mixture of one see several colors and patterns. These are composition or more minerals. usually bits and pieces of different minerals. Rocks can be huge boulders or small The mix of minerals in one kind of rock helps Size pebbles. They can be as big as a you tell it apart from other kinds of rocks. mountain or as tiny as a speck of dust. elements → minerals → rocks Rocks can be flat, round, square, Shape or almost any other shape. Rocks come in every color you can imagine. Many rocks have more than Color one color, depending on the colors of their minerals. Some rocks feel very rough, while others are smooth. They can have tiny grains; Texture large, smooth chunks; or long, pointed crystals. Some rocks are full of airholes. The Mohs Scale of Hardness compares how hard each mineral is within a Hardness rock. Talc is rated a 1 (very soft), and diamonds are rated a 10 (very hard). Rocks may have streaks, waves, or straight lines. They may have dots Patterns everywhere or be built layer upon layer. Some rocks do not have a clear pattern. Each rock is made up of a certain mixture of minerals. An important way to describe a rock is by where in nature it is found. A beach Location may have different rocks than a forest, desert, or volcano. 7 8 Rock Groups Igneous rocks can be very different from When you think of “rock groups,” you might one another. The imagine loud music. But Earth has its own size of the crystals kinds of rock groups. Every rock belongs in in an igneous rock one of three groups, based on how it formed. Pumice is full of tiny airholes. It’s is determined by so light that it can float in water! Let’s take a closer look at each